Many known absorbent articles such as diapers, incontinence articles, feminine hygiene products, and training pants, typically comprise absorbent core materials located between a liquid pervious bodyside liner or topsheet and a vapor permeable, liquid impermeable backsheet. The bodyside liner allows bodily liquids to flow through easily towards the absorbent core. The absorbent core takes up the liquids quickly. Thus, no excessive pooling of liquids occurs on the body-facing surface of the absorbent article. The outer cover is typically liquid impermeable such that there is no leakage from the absorbent article. Since, however, the disposable absorbent article may be worn for hours after coming in contact with body exudates and perspiration from the wearer's body, liquid vapors escaping from the absorbent core often get entrapped in the space between the absorbent article and the wearer's skin, resulting in an increased relative humidity in the occluded area. As is known in the art, the increased relative humidity leads to discomfort and overhydrated skin that is prone to skin health problems, especially rashes and other contact dermatitis.
Such backsheets are well suited to prevent the leakage of bodily fluids (such as urine, menses or fecal matter) from the absorbent material to the outer garment of a wearer. Unfortunately, the use of such an impermeable backsheet can result in a high degree of humidity in the absorbent article when the absorbent article is in use such that relatively elevated skin hydration levels may result.
Attempts at remedying this problem have included utilizing microporous or monolithic films as backsheet materials which then allow air and water vapor diffusion. Others have tried incorporating high permeability zones within the absorbent core, such as by aperturing the absorbent core or by creating portions in the core containing substantially less high absorbency materials than in other portions of the core. Absorbent articles relying on these technologies have still tended to exhibit significantly increased relative humidity between the skin of the wearer and the article when the article is loaded with liquids.
One phenomenon of particular interest that affects a loaded or wet absorbent article is any pressure or impact force due to the wearer's motion, such as sitting, walking, bending, and falling. Known absorbent articles still tend to fail to hold liquids when they are loaded to their absorbent capacity especially when the loaded absorbent article is under pressure or impact due to a wearer's motion.
It has been observed by the Applicants that convective vapor flow is much more effective than diffusive vapor flow when there is a damp absorbent article core present. Consequently, there is a need for absorbent articles which deliver a combination of benefits to the wearer. These benefits should include an improved liquid impact capability, breathability (i.e., air vapor flow via convection), water vapor transmission (i.e., through diffusion) and resistance to leakage under impact or sustained pressure.